On-board radiation sensing apparatus

ABSTRACT

Systems, methods, and apparatuses for providing on-board electromagnetic radiation sensing using beam splitting in a radiation sensing apparatus. The radiation sensing apparatuses can include a micro-mirror chip including a plurality of light reflecting surfaces. The apparatuses can also include an image sensor including an imaging surface. The apparatuses can also include a beamsplitter unit located between the micro-mirror chip and the image sensor. The beamsplitter unit can include a beamsplitter that includes a partially-reflective surface that is oblique to the imaging surface and the micro-mirror chip. The apparatuses can also include an enclosure configured to enclose at least the beamsplitter and a light source. With the apparatuses, the light source can be attached to a printed circuit board (PCB). Also, the enclosure can include an inner surface that has an angled reflective surface that is configured to reflect light from the light source in a direction towards the beamsplitter.

RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 17/154,994, filed Jan. 21, 2021 which is acontinuation application of U.S. patent application Ser. No. 16/400,780,filed May 1, 2019, issued as U.S. Pat. No. 10,900,842 on Jan. 26, 2021,which claims priority to U.S. Prov. App. Ser. No. 62/791,193, filed Jan.11, 2019, entitled “ON-BOARD RADIATION SENSING APPARATUS”, U.S. Prov.App. Ser. No. 62/791,195, filed Jan. 11, 2019, entitled “SEQUENTIAL BEAMSPLITTING IN A RADIATION SENSING APPARATUS”, and U.S. Prov. App. Ser.No. 62/791,479, filed Jan. 11, 2019, entitled “RADIATION SENSINGAPPARATUS WITH A LIGHT SOURCE MOUNTED ON A FLEXIBLE PART”, thedisclosure of which applications are hereby incorporated by referenceherein in their entirety.

FIELD OF THE TECHNOLOGY

At least some embodiments disclosed herein relate to on-boardelectromagnetic radiation detection using micromechanical radiationsensing pixels in general and more particularly but not limited to theon-board sensing of infrared (IR) radiation.

And, at least some embodiments disclosed herein relate toelectromagnetic radiation detection using beam splitting in general andmore particularly but not limited to the sensing of infrared (IR)radiation using beam splitting in a radiation sensing apparatus with thelight source mounted on a flexible part. Also, disclosed herein is aprinted circuit board arrangement with a flexible part for anelectromagnetic radiation detector.

BACKGROUND

U.S. Pat. No. 9,857,229 discloses a method of fabricatingelectromagnetic radiation detection devices including: forming a firstmask on a substrate; forming a structural layer on the substrate usingthe first mask; forming a metallic layer overlying the structural layer;removing the first mask; forming a second mask on the substrate, thesecond mask having mask openings; selectively patterning the metalliclayer using the mask openings; and removing the second mask. The entiredisclosure of U.S. Pat. No. 9,857,229 is hereby incorporated herein byreference.

U.S. Pat. No. 5,929,440 discloses an electromagnetic radiation detectorthat has an array of multi-layered cantilevers. Each of the cantileversis configured to absorb electromagnetic radiation to generate heat andthus bend under the heat proportionately to the amount of absorbedelectromagnetic radiation. The cantilevers are illuminated and lightreflected by the bent cantilevers are sensed to determine the amount ofelectromagnetic radiation. The entire disclosure of U.S. Pat. No.5,929,440 is hereby incorporated herein by reference.

U.S. Pat. No. 9,851,256 discloses a radiation detection sensor includinga plurality of micromechanical radiation sensing pixels having areflecting top surface and configured to deflect light incident on thereflective surface as a function of an intensity of sensed radiation.The sensor can provide adjustable sensitivity and measurement range. Theentire disclosure of U.S. Pat. No. 9,851,256 is hereby incorporatedherein by reference.

U.S. Pat. No. 9,810,581 discloses an electromagnetic radiation sensingmicromechanical device to be utilized in high pixel-density pixel sensorarrays. Arrays of the device can be utilized as IR imaging detectors.The entire disclosure of U.S. Pat. No. 9,810,581 is hereby incorporatedherein by reference.

SUMMARY OF THE DESCRIPTION

Described herein are systems, methods, and apparatuses for providingon-board electromagnetic radiation sensing using beam splitting in aradiation sensing apparatus. The beam splitting can occur by a beamsplitter such as a partial reflecting surface or a partially-transparentand partially-reflective (light directing) optical element. It is to beunderstood that a beamsplitter can be or include a light directingdevice generally. For example, the beamsplitter can be or include aprism. The radiation sensing apparatuses can include a micro-mirror chipincluding a plurality of light reflecting surfaces. The apparatuses canalso include an image sensor having an imaging surface. The apparatusescan also include a beamsplitter unit located between the micro-mirrorchip and the image sensor. The beamsplitter unit can include abeamsplitter that includes a reflective surface that is oblique to theimaging surface and the micro-mirror chip. The apparatuses can alsoinclude an enclosure configured to enclose at least the beamsplitter anda light source. With the apparatuses, the light source can be attachedto a printed circuit board (PCB). Also, the enclosure can include aninner surface that has an angled reflective surface that is configuredto reflect light from the light source in a direction towards thebeamsplitter. The apparatuses can be utilized for human detection, firedetection, gas detection, temperature measurements, environmentalmonitoring, energy saving, behavior analysis, surveillance, informationgathering and for human-machine interfaces. To put it another way, theapparatuses can be coupled to or controlled from a facility or featureincorporated into a circuit board of a computer or computerized device,such as a mobile device, to provide human detection, fire detection, gasdetection, temperature measurements, environmental monitoring, energysaving, behavior analysis, surveillance, information gathering and forhuman-machine interfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousembodiments of the disclosure.

FIG. 1 illustrates an apparatus 100 configured to measure a distributionof electromagnetic radiation according to at least one embodiment wherethe light source is on the printed circuit board.

FIG. 2 illustrates some parts of the apparatus illustrated in FIG. 1 ,and further illustrates the micro-mirror chip of the apparatus.

FIG. 3 illustrates some parts of the apparatus illustrated in FIG. 1 ,and further illustrates the beamsplitter unit of the apparatus.

FIG. 4 illustrates some parts of the apparatus illustrated in FIG. 1 ,and further illustrates mechanisms for displacements of reflected lightrays on the imaging surface of the apparatus to determine the intensityof electromagnetic radiation on micro mirrors of the apparatus.

FIG. 5 illustrates another apparatus 500 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the light source is part of the printed circuitboard and the beamsplitter unit implements sequential beam splitting.

FIGS. 6A, 6B, and 6C illustrate a construction for the structure of thebeamsplitter unit according to at least one embodiment such as theembodiment illustrated in FIG. 5 where the beamsplitter unit implementssequential beam splitting.

FIG. 7 illustrates another apparatus 700 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a signal processing unit is integrated with ordirectly attached to the image sensor.

FIG. 8 illustrates another apparatus 800 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a radiation lens and a radiation filter arewithin an opening of the enclosure that is above the micro-mirror chip.

FIG. 9 illustrates another apparatus 900 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a radiation lens, a radiation filter, and themicro-mirror chip are within an opening of the enclosure that is abovethe beamsplitter unit.

FIG. 10 illustrates another apparatus 1000 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a radiation lens and a radiation filter arewithin an opening of the enclosure that is above the beamsplitter unit,and where the micro-mirror chip is partially within the opening.

FIG. 11 illustrates another apparatus 1100 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a radiation filter is within an opening of theenclosure that is above the micro-mirror chip and the radiation lens 120is external to the apparatus, such as on a separate apparatus orstructure.

FIG. 12 illustrates another apparatus 1200 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the apparatus includes a light source mounted ona flexible part.

DETAILED DESCRIPTION

The following description and drawings are illustrative and are not tobe construed as limiting. Numerous specific details are described toprovide a thorough understanding. However, in certain instances, wellknown or conventional details are not described in order to avoidobscuring the description.

FIG. 1 illustrates an on-board electromagnetic radiation sensingapparatus 100 configured to measure a distribution of electromagneticradiation (such as infrared radiation) according to at least oneembodiment. For this disclosure it is to be understood that an on-boardelectromagnetic radiation sensing apparatus is a type of electromagneticradiation sensing apparatus that can be coupled to or controlled from afacility or feature incorporated into a circuit board of a computer orcomputerized device such as a mobile device.

In general, the apparatus (such as apparatus 100 illustrated in FIG. 1 )includes a light directing device configured to direct light rays from alight source (such as the light source 126) to light reflecting areas ofthe micro mirrors of the micro-mirror chip 102. Further included is animaging area facing the light reflecting area of the micro mirror thatis configured to receive reflected light spots formed by the reflectionsof light rays directed onto the light reflecting area of the micromirror. Further included is an enclosure configured to enclose the lightdirecting device and the imaging area when the light directing deviceand imaging area are attached to a printed circuit board (PCB). Also, inexemplary embodiments, the enclosure includes an inner surface that hasan angled partially reflective plane (such as a 45-degree reflectiveplane) that is part of the light directing device. The light directingdevice can include an optical filter. Further, the light directingdevice can include a spherical surface facing the light source, whichcan act as a collimator. The optical filter can be integrated with thecollimator or with other planes of the light directing device. Also, insome embodiments, a radiation imaging lens 120 can be included toproject environmental radiation onto radiation absorbing surfaces ofmicro mirrors of the micro-mirror chip 102. The radiation lens (such asan infrared radiation lens) can be a part of the enclosure. Also, animage sensor 104 can be included to capture an image of light spotsreflected from the micro mirrors of the micro-mirror chip 102 and formedon the imaging surface. Further, a signal processing unit can beincluded to correlate and identify light spots on the image to differentmicro mirrors and calculate a radiation intensity absorbed by eachindividual micro-mirror through its corresponding light spot motion orlight pattern change captured by the image sensor 104.

In FIG. 1 , the electronic components of the apparatus 100 are mountedon a PCB 101. The apparatus 100 can be mounted on or attached to a hostor carrier PCB, such as one in a mobile device or used to form aseparate radiation sensing device that has a wired or wireless datacommunication capability. The apparatus 100 includes a micro-mirror chip102, an image sensor 104, and a beamsplitter unit 106 located betweenthe micro-mirror chip 102 and the image sensor 104. The micro-mirrorchip 102 includes a plurality of micro-mirrors that have lightreflecting surfaces 108 that are illustrated in detail in FIGS. 2-4 .The image sensor 104 includes an imaging surface 110. The beamsplitterunit 106 includes a beamsplitter 112, which partially transmits andpartially reflects light. A length of the beamsplitter 112 is alignedalong a horizontal axis (i.e., the y-axis) that is parallel to themicro-mirror chip and the imaging surface. The horizontal axis (i.e.,the y-axis) is perpendicular to the vertical axis (i.e., the z-axis) andan axis going into and out of the plane illustrated in FIGS. 1-6 (i.e.,the x-axis). The x-axis is not shown in FIGS. 1-5 and 7-10 .

In FIG. 1 , there is a single beamsplitter and beamsplitter unit betweenthe micro-mirror chip 102 and the image sensor 104. The beamsplitter 112can have a rectangular cross section in the yz plan. Further, thebeamsplitter 112 includes a partially-reflective surface 114 that isoblique to the imaging surface 110 and the micro-mirror chip 102 andthat can extend across more than half the height of the beamsplitter112. In FIG. 1 , the partially-reflective surface 114 extends across theheight of the beamsplitter 112.

As illustrated, the micro-mirror chip 102 can be directly fixed toand/or positioned on the beamsplitter unit 106 and the beamsplitter unit106 can be directly fixed to or mounted on the image sensor 104.

The micro-mirror chip 102 includes a set of micro mirrors that arefurther illustrated in detail in FIGS. 2-4 . A micro mirror includes aradiation absorbing area and a light reflecting area. The micro mirrorchanges in orientation or position in response to radiation absorbed inthe radiation absorbing area. For example, the micro-mirror chip 102 caninclude a set of micro mirrors formed on a substrate. Each mirror can bea plate having bi-material legs standing on a frame of the substrate.The reflective surface of each mirror plate can be part of a metal layerto form the plurality of light reflecting surfaces 108. The substratelayer of the mirror plate absorbs radiation (such as infrared radiation)to raise the temperate of the plate. The radiation absorption surfacecan be on the opposite side of the plate from the reflective surface.The bi-material legs bend according to the plate template to rotate theplate and hence the reflective surface. The rotation angle of the platerepresents the temperature and/or the intensity of the absorbedradiation by the plate. Some additional aspects of some embodiments ofthe micro-mirror chip 102 are disclosed in U.S. Pat. No. 9,810,581.

The image sensor 104 can be a CMOS (or CCD) based image sensor. Theimage sensor 104 can be connected to or include an integrated signalprocessor such as an integrated ASIC, microcontroller, microprocessor orfield-programmable gate array (FPGA). In some embodiments, a signalprocessor can be connected via the PCB 101 (e.g., see signal processingunit 702 of FIG. 7 ). The CMOS image sensor can be configured to receiverays of light reflected from the micro-mirror chip, in the purpose ofdetecting certain electromagnetic radiation such as infrared (IR)radiation according to this system; and the rows and columns of lightdots or light patterns reflected by the micro-mirrors and captured bythe CMOS image sensor can be analyzed to measure the deflected distancesof the light dots and thus the radiation intensity or temperature of theradiation image formed on the micro-mirror chip.

As illustrated in FIG. 1 , the radiation sensing apparatus 100 can alsoinclude an enclosure 132 configured to enclose the beamsplitter 112 anda light source 126. The light source 126 is attached to the PCB 101. Forexample, the light source 126 can be a light emitting diode (LED)mounted on the PCB 101 and connected to the circuit formed on the PCB101. The light source 126 can be a LED with an emissivity of blue color(e.g. 450 nm wavelength), white light, UV light or any color in thevisible or near IR spectrum. The enclosure 132 includes interiorsurfaces that include an angled reflective surface 136 that isconfigured to reflect light rays 134, 134′, and 134″ from the lightsource 126 towards the beamsplitter 112 as reflected light rays 118 a,118 a′, and 118 a″. The reflective surface 136 is positioned between thelight source 126 and a lens (116) such that the mirror image of thelight source as reflected by the surface 136 as a mirror is positionedat a focal point of the lens 116. Thus, the lens 116 converts thenon-collimated and diverging lights 118 a, 118 a′, and 118 a′ from thepoint light source (126) as reflected by the surface 136 into collimatedlight rays 118 b, 118 b′, and 118 b″ that are parallel to the imagingsurface and the micro-mirror chip 102. The collimated light rays can besubstantially parallel (as shown in FIG. 1 schematically), or slightlyconverging or diverging. In some embodiments, the lens 116 can have aflat surface and if the light source is at a distance which issubstantially larger than the height of the lens then the light rays arerefracted upon entering the beam splitter, and thus diverge within thebeamsplitter element. In some embodiments, a spherical or asphericalsurface of the lens is not needed and the lens can have a flat surfaceand the schematically shown parallel light rays can be diverging. Thereflective surface allows the light source 126 to be mounted on the PCB101, directing lights in a direction substantially perpendicular to thePCB 101. Such an arrangement can reduce the length (e.g., in the y axis)of the device and/or simplify the procedure for assembling componentduring manufacturing of the apparatus 100. The enclosure 132 alsoincludes interior surfaces 144, 146, and 148 that can be non-reflectiveand/or less reflective than the surface 136; and the enclosure 132 hasexterior surfaces 150, 152, and 154. Exterior surfaces 152 and 154 areside surfaces of the enclosure 132, and exterior surface 150 is a topexterior surface of the enclosure 132. The exterior surface 150 includesan opening 140 to a chamber 156 of the enclosure 132. The opening 140traverses a top wall of the enclosure 132 from the exterior surface 150of the top wall to the interior surface 146 of the top wall. The purposeof the opening 140 can be to position and/or fix the lens 120.

The interior surface 144 is side interior surface next to the angledreflective surface 136 and parallel to the z-axis. Interior surface 146is a top interior surface next to the angled reflective surface 136 andperpendicular to the z-axis and the interior surface 144. The angledreflective surface 136 is between the surfaces 144 and 146. Interiorsurface 148 is a side interior surface next to the interior surface 146and is shown parallel to the z-axis and the interior surface 144. Theinterior surface 148 faces the interior surface 144 and the angledreflective surface 136. The micro-mirror chip 102, the beamsplitter unit106, and the image sensor 104 are housed within the interior surfaces144, 146, and 148 as well as the angled reflective surface 136. Theseinterior surfaces with the upper surface of the PCB 101 form the chamber156 configured to enclose the micro-mirror chip 102, the image sensor104, and the beamsplitter 106. The enclosure can be sealed orhermetically sealed to isolate the chamber 156 from light, radiation,humidity, particles, gases or dust pollution.

Also, the chamber 156 includes the angled reflective surface 136 that isoblique to the imaging surface 110 and the micro-mirror chip 102 andconfigured to reflect light from the light source 126 towards thebeamsplitter 112.

In some embodiments, the chamber 156 houses the micro-mirror chip 102,the image sensor 104, and the beamsplitter 106 entirely. In someembodiments, the micro-mirror chip 102 is partially within the openingof the enclosure and partially within the chamber 156.

FIGS. 1, 5, 7, 8, 9, 10, and 11 illustrate some different embodiments ofthe enclosure of the apparatus. These different embodiments aredescribed in more detail herein. In general, as shown in FIGS. 1, 5, 7,and 8 , the enclosure 132 (or enclosure 832 of FIG. 8 ) is configured toenclose the micro-mirror chip 102, the light reflecting surfaces 108,the imaging surface 110, the imaging sensor 104, and the beamsplitterunit 106. As shown in FIG. 10 , the enclosure 1032 is configured toenclose the light reflecting surfaces 108, the imaging surface 110, theimaging sensor 104, and the beamsplitter unit 106. As shown in FIG. 9 ,the enclosure 932 is configured to enclose the imaging surface 110, theimaging sensor 104, and the beamsplitter unit 106.

Also, as shown in FIGS. 8-10 , the enclosures 832, 932, and 1032 canoptionally include a radiation filter 122 within the respective openings840, 940, and 1040 of the enclosures and between the radiation lens 120and the micro-mirror chip 102 such that radiation 124 b that emits fromthe radiation lens passes through the radiation filter 122 onto theplurality of radiation absorption surfaces of the micro-mirror chip 102.

Further, shown in FIG. 1 as well as some of the other drawings, theenclosure 132 is attached to the PCB 101 by pins 142. In this sense, theenclosure 132 is a housing of the apparatus 100 attached to the PCB 101by pins 142. The pins 142 can be configured to fit and align theenclosure 132 to the PCB 101. Alternatively, instead of using alignmentpins 142 to align and fix the enclosure 132 to the PCB 101, these partsas well as other parts of the overall system can be aligned by differentmeans and fixed to each other with glue. Alignment pins can be presenton the beamsplitter to align and fix it to the PCB 101, with the imagesensor 104 being in between the beamsplitter and the PCB 101.

Also, as depicted in FIG. 1 , the light source 126 emits light rays,including light ray 134, upwards in the general direction of the z-axis.To reflect light towards a lens 116 integrated with the beamsplitterunit 112, the enclosure 132 includes the angled reflective surface 136that is skewed from the z-axis at angle 138. In some embodiments, theangle 138 is 45 degrees so that a center ray, e.g., light ray 134, ofthe light rays emitted by the light source 126, is reflected at a90-degree angle towards the lens 116. In such embodiments, the angledreflective surface 136 is a 45-degree reflective surface that is 45degrees from the imaging surface 110, for example. Also, in suchembodiments, when the light source 126 emits a center light ray alongthe z-axis (such as light ray 134), the 45-degree reflective surface isconfigured to reflect the center light ray at a 90-degree angle in adirection towards the beamsplitter 112. Further, as shown in FIG. 1 ,the partially-reflective surface 114 of the beamsplitter 112 can beparallel to the angled reflective surface 136. Thus, in embodiments witha 45-degree partially-reflective surface 114 that is 45 degrees from theimaging surface and 45 degrees from the micro-mirror chip, the angledreflective surface 136 can be 45 degrees from the imaging surface and 45degrees from the micro-mirror chip as well.

As illustrated in FIG. 1 , the lens 116 can be integrated with thebeamsplitter unit 106. In some embodiments, the lens 116 can beintegrated by cutting the right-side half of the lens 116 off to have aflat surface to attach the lens to the flat surface of the beamsplitterunit 106. In some other embodiments, the lens 116 is formed directly onthe beamsplitter unit 106.

The lens 116 is shown configured to direct light rays, such as lightrays 118 a, 118 a′, and 118 a″, onto a partially-reflective surface 114of the beamsplitter 112 as light rays 118 b, 118 b′, and 118 b″respectively. Specifically, the lens 116 collimates and producesparallel light rays from the light rays 118 a, 118 a′ and 118 a″ fromthe light source 126, which can be a point source, as reflected by thesurface 136. The lens 116 collimates non-collimated light rays 118 a,118 a′, and 118 a″ into collimated light rays 118 b, 118 b′, and 118 b″respectively. A sphere or at least a partial sphere can be the basis forthe lens that makes the rays of light parallel. The non-collimated lightrays 118 a, 118 a′, and 118 a″ are reflected light rays reflected fromthe angled reflective surface 136 which is an interior surface of theenclosure 132. It is to be understood that the parallel light raysdescribed herein can be substantially parallel light rays. In someembodiments the reflective surface may not be flat and can be sphericalor aspherical in order to compensate optical aberrations of the lens tocreate a better collimation of light rays. In some embodiments the lightrays do not have to be parallel or substantially parallel, but canconverge slightly in order to project a smaller image of themicro-mirrors onto the image surface. Nevertheless, the center light raycan run parallel or substantially parallel to the image surface planeand the micro-mirror plane, whilst the outer light rays converge towardsthe center light ray.

Initially, a light source 126 emits light rays 134, 134′, and 134″towards the angled reflective surface 136, and then the non-collimatedlight rays 118 a, 118 a′, and 118 a″ are reflected from the angledreflective surface 136. The light source 126 can include a lightemitting diode (LED). As shown, the light source 126 is directlyattached to the PCB 101. The light rays 134, 134′, and 134″ can beemitted as a cone shape with the tip of the cone shape at the lightsource 126. To direct these rays, which can be emitted in a cone shapeand can also be reflected off the angled reflective surface 136 in ashape somewhat similar to a cone shape, the lens 116 converts the rays118 a, 118 a′, and 118 a″ to parallel light rays 118 b, 118 b′, and 118b″ for entering the beamsplitter 112.

In examples using an LED, the light source 126 can include or beintegrated with a pinhole, a cone or an emission light directing device(such as a reflector or aperture stops). In such examples, the LED canbe configured to emit rays of light, such as visible light, upwards fromthe PCB according to the pinhole and the cone. The light in suchexamples is restricted and/or defined by the pinhole or the lightdirecting devices.

As illustrated in FIG. 1 partially, the partially-reflective surface 114splits each of the collimated light rays 118 b, 118 b′, and 118 b″ splitinto two light rays. For example, the partially-reflective surface 114splits the incoming collimated light ray 118 b into a light ray 118 creflected towards the micro-mirror chip 102 and a light ray 118 e thatpenetrates through the partially-reflective surface 114. The collimatedlight rays each split into two light rays at the partially-reflectivesurface 114 of the beamsplitter 112. The light rays 118 b, 118 b′, and118 b″ are reflected by the beamsplitter 112 off of the reflectivesurface 114 to become light rays 118 c, 118 c′, and 118 c″ travellingtowards the plurality of light reflecting surfaces 108 of themicro-mirror chip 102, and the light rays 118 e, 118 e′, and 118 e″(which are shown in FIG. 3 ) transmit through the reflective surface 114of the beamsplitter 112. These initially transmitted light rays 118 e,118 e′, and 118 e″ have no functionality in the operating principle ofthe apparatus. These light rays can either exit the beamsplitter or theback side of the beamsplitter or the backside can be light absorbing sothese light rays get absorbed or scattered on the beamsplitter surface106 a. The light rays 118 c, 118 c′, and 118 c″ are shown reflecting offthree of the reflecting surfaces of the plurality of light reflectingsurfaces 108 as light rays 118 d, 118 d′, and 118 d″, respectively. Thelight rays 118 d, 118 d′, and 118 d″ are again split by thepartially-reflective surface 114 where the penetrating rays go towardsthe imaging surface 110 of the image sensor 104 as light rays 118 dd,118 dd′, and 118 dd″, respectively (e.g., See FIG. 3 ). As the lightrays 118 d, 118 d′, and 118 d″ pass again through partially-reflectivesurface 114 a portion of these light rays will be reflected towards thelens 116.

In some embodiments, the beamsplitter is configured to split an incominglight ray from the light source into a first light ray and a secondlight ray, where the first light ray is reflected by the beamsplittertowards the plurality of light reflecting surfaces of the micro-mirrorchip and the second light ray passes through the beamsplitter towards asidewall of the enclosure (such as sidewall 148). Preferably, thesidewall 148 is non-reflective and absorbs the second light ray. In suchembodiments, each light reflecting surface of the plurality of lightreflecting surfaces of the micro-mirror chip can reflect a light raythat is split again at the reflective surface of the beamsplitter into athird light ray and a fourth light ray such that the third light raypasses through the reflective surface to the imaging surface of theimage sensor and the fourth light ray is reflected to towards the lightsource 126.

As illustrated in FIG. 1 , a radiation lens 120 can be used to directradiation rays 124 a, through an optional radiation filter 122, towardsmicro mirrors of the micro-mirror chip 102. As shown the lens 120 islocated in the opening 140 directly above a housing 128 of a radiationfilter 122 and the micro-mirror chip 102. In this sense, the enclosure132 includes the radiation lens 120 within the opening 140 of theenclosure, and the opening 140 is located above the micro-mirror chip102 such that radiation that passes through the opening and theradiation lens 120 emits onto a plurality of radiation absorptionsurfaces of the micro-mirror chip 102 (e.g., radiation absorptionsurfaces 204 illustrated in FIG. 2 ). In some embodiments, the radiationlens 120 is embedded within a cone enclosure that can be fitted into theopening of the enclosure or some other fitting mechanism to fit anoptical lens into a housing (e.g., gluing, press-fit, retaining ring,thread, etc).

As illustrated in FIG. 1 , the apparatus can contain an aperture,aperture stop or generally a light ray guiding or restricting structure,such as schematically shown with simple plates in its cross section 161a and 161 b, within the chamber 156, between the light source 126 andthe beamsplitter unit 106. The functionality of such light ray guidingor restricting structure is to eliminate parasitic light scatter. Forexample, the light source 126 can be a point source with an emissivityangle of 180 degree. Some light rays can travel directly from the lightsource towards the direction of the beamsplitter unit 106 and can causeunwanted parasitic (“stray light”) or disturbing pattern or hinder thelight rays to be collimated. In other instances, some reflected lightrays of surface 136 may be outside the cone and/or entrance angle and bepositioned in such way that they travel from surface 136 towards surface146 and reflect off surface 146 to enter the beamsplitter causing someunwanted light patterns onto the imaging surface. A light ray guiding orrestricting structure, such as a simple circular or other opening canhelp or define light rays to form an opening cone. This can includelight rays to travel from the aperture of lens 116 to the point sourcesuch as the focal point of the lens 116. A light ray guiding orrestricting structure can be part of the enclosure 132, as illustratedwith structure 161 a. A light ray guiding or restricting structure canbe mounted onto the PCB 101 as illustrated with 161 b. In someinstances, a light ray guiding or restricting structure can be aseparate part positioned within the chamber 156.

FIG. 2 illustrates some parts of the apparatus 100 illustrated in FIG. 1, and further illustrates the micro-mirror chip 102 of the apparatus100.

As shown in FIG. 2 , the radiation filter 122 can filter the directedradiation before the radiation is received by micro mirrors 202.Specifically, as shown, the radiation filter 122 can filter the directedradiation before the radiation is received by radiation absorptionsurfaces 204 of the micro mirrors 202. Reflective surfaces of themicro-mirrors provide the plurality of light reflecting surfaces 108.Also, as shown, the plurality of light reflecting surfaces 108 are onrespective opposing sides to respective radiation absorption surfaces204.

In general, light emitted from a light emitting source (such as thelight source 126, which can be or include a light emitting diode) iseventually reflected off the plurality of light reflecting surfaces 108of the micro-mirror chip 102 according to the orientations of theplurality of light reflecting surfaces 108. And, the orientations resultfrom the respective amounts of radiation received by each of theradiation absorption surfaces 204 of the micro-mirror chip 102. Theorientations of the light reflecting surfaces 108 effect the angles 312,314, and 316 depicted in FIG. 3 . FIG. 2 illustrates the radiation rays124 c causing certain micro mirrors 202 to change in orientation, andthus effecting the angle in which light rays 118 c, 118 c′, and 118 c″reflect off each of the respective surfaces of the plurality of lightreflecting surfaces 108 as respective reflected light rays 118 d, 118d′, and 118 d″.

As shown in FIG. 1 , the lens 120 can be above the housing 128 of theradiation filter 122 and the micro-mirror chip 102. The lens 120 isshown in FIGS. 1 and 2 as configured to direct rays of radiation, suchas radiation rays 124 a, to the radiation filter 122 as radiation rays124 b (as shown in FIG. 2 ).

The radiation filter 122 can have different filtering characteristics.For example, the radiation imaging lens can be an infrared lens made ofe.g., Germanium, Silicon, polymer, chalcogenide, glass and the like.

As shown in FIG. 2 , the radiation imaging lens is arranged in relationwith micro mirrors 202 of the micro-mirror chip 102 to form an image ofthe radiation (e.g., infrared radiation) on a mirror plane 200 of themicro mirrors 202. The radiation image is derived from radiation rays124 c.

The radiation intensity provided by radiation rays 124 c can correspondto light ray displacement on the imaging surface 110 of the image sensor104 (such as light ray displacements 402 and 404 as shown in FIG. 4 ).Light ray displacement, produced by a respective micro mirror of themicro mirrors 202, corresponds to the intensity of a pixel of theradiation image derived from the radiation filter 122 at the location ofthe respective micro mirror. Light ray displacement can be generallycaused by the displacement of the micro-mirrors. Micro-mirrors can bedisplaced by absorbing radiation. In some instances, micro-mirrors aredisplaced through gravitational forces, and/or through its operationaltemperature fluctuation. To distinguish between incoming radiationdisplacement versus parasitic (e.g., gravitational or operationaltemperature) displacement, reference micro-mirror(s) can be implementedwhich are hidden from radiation flux, but deflect only from gravity oroperational temperature variation.

As shown in FIG. 1 , the plurality of light reflecting surfaces 108faces the imaging surface 110, and as illustrated in FIG. 2 , each lightreflecting surface of the plurality of light reflecting surfaces 108includes a mirror that moves independent of the other mirrors of theplurality of light reflecting surfaces 108 according to radiation sensedand/or absorbed by the radiation absorption surfaces 204.

In some embodiments, the micro-mirror chip can include a glass capfacing downwards towards the image surface and a radiation transparentcap facing upwards towards the lens 120.

In some embodiments, the micro-mirror chip includes at least one row ofmicro mirrors arranged along a first direction in a first plane, eachrespective micro mirror in the row of micro mirrors having a radiationabsorbing surface and a light reflecting area positioned at an oppositeside of the radiation absorbing surface, where the respective micromirror is configured to rotate along a second direction in the firstplane in response to radiation absorbed in the radiation absorbingsurface. In such embodiments, a CMOS image sensor can include an imagingsurface facing the light reflecting area of the respective micro mirrorto receive a reflected light ray of the respective light ray directedonto the light reflecting area of the respective micro mirror, theimaging surface positioned in relation with the row of micro mirrors toproduce equal displacements of light rays reflected from at least two ofthe row of micro mirrors onto the imaging surface for equal rotationsalong the second direction in the row of micro mirrors. In suchembodiments, the CMOS image sensor can include an imaging surface facingthe light reflecting area of the respective micro mirror to receivelights of different optical characteristics reflected from differentmicro mirrors in the row. The different optical characteristics caninclude different light intensities. Also, the different opticalcharacteristics can include different shapes of the light. Further thedisplacements of the micro-mirrors can result in projecting a changingpattern on the image surface.

FIG. 3 illustrates some parts of the apparatus 100 illustrated in FIG. 1, and further illustrates the beamsplitter unit 106 of the apparatus.

As illustrated in FIGS. 1 and 3 , the length of the beamsplitter 112 isoriented in a direction 130 that is parallel to the micro-mirror chip102 and the imaging surface 110. Note that the direction 130 is alsoshown in FIGS. 1-5 and 7-10 as a direction of reference for the otheraspects of and related to the apparatus 100.

As shown in FIG. 3 as well as FIG. 1 , the beamsplitter unit 106includes beamsplitter 112 including a semi-reflective andsemi-transparent surface 114 that is oblique to the imaging surface 110and the micro-mirror chip 102. As shown, the reflective surface 114 canextend across more than half the height of the beamsplitter. As shown,the reflective surface 114 extends across the height of the beamsplitter112. The reflective surface 114 can be coated with an optical film thatcauses exactly 50:50 reflection-transmission splitting of light rays atthe surface.

As illustrated in FIG. 3 , the partially-reflective surface 114 isoblique to the imaging surface 110 at an angle 302. Thepartially-reflective surface 114 is oblique to the micro-mirror chip 102at an angle 304. As described in detail herein, in some embodiments, theangles 302 and 304 are 45-degree angles. In some embodiments, thebeamsplitter 112 is arranged in a direction that is not parallel to themicro-mirror chip 102 and/or the imaging surface 110, the angles 302 and304 are different from each other (not shown in the drawings). Also, insome embodiments, the angles 302 and 304 can be the same but are lessthan or greater than 45-degree angles.

As shown in FIG. 3 , the beamsplitter 112 is configured to split lightrays 118 b, 118 b′, and 118 b″ to light rays 118 c, 118 c′, and 118 c″and light rays 118 e, 118 e′, and 118 e″, respectively. As shown, thelight rays 118 c, 118 c′, and 118 c″ reflect from the beamsplitter 112at the partially-reflective surface 114 at angles 306, 308, and 310,respectively, toward the micro-mirror chip 102. The light rays 118 e,118 e′, and 118 e″ pass through the beamsplitter 112 towards the back ofthe beamsplitter unit 106. Each light reflecting surface of theplurality of light reflecting surfaces 108 of the micro-mirror chip 102reflects light rays 118 d, 118 d′, and 118 d″, at angles 312, 314, and316 respectively, which are split again at the partially-reflectivesurface 114 as the penetrating light rays 118 dd, 118 dd′, and 118 dd″towards the image sensor 104, respectively, and other light rays backtowards the lens 116 (not shown in the drawings). The light rays 118 dd,118 dd′, and 118 dd″ pass through the partially-reflective surface 114to reach the imaging surface 110 of the image sensor 104.

In some embodiments, the beamsplitter unit includes a beamsplitterhaving a 45-degree partially-reflective surface that is 45 degrees fromthe imaging surface and 45 degrees from the micro-mirror chip. The first45-degree reflective surface can extend across more than half the heightof the beamsplitter (e.g., the 45-degree reflective surface can extendacross the entire height of the beamsplitter). As mentioned herein, eachof angles 302 and 304 can be 45 degrees. This can occur when the lengthof the beamsplitter is aligned horizontally with and parallel to themicro-mirror chip and the imaging surface of the image sensor. Althoughit appears in FIG. 3 that the angles 302 and 204 are approximately 45degrees, for the present disclosure it shall be understood that theaforesaid angles can vary.

In such embodiments with the beamsplitter having a 45-degree reflectivesurface and its length being aligned in parallel to the micro-mirrorchip and the imaging surface, the angles 306, 308, and 310 can be90-degree angles with respect to the direction 130 (the direction 130being parallel to the micro-mirror chip 102 and the imaging surface110). To put it another way, in such embodiments, the angles 306, 308,and 310 are 90-degree angles with respect to the micro-mirror chip 102and the imaging surface 110. In such embodiments, when light reflectingsurfaces of the plurality of light reflecting surfaces 108 that reflectthe light rays 118 c, 118 c′, and 118 c″ are aligned parallel to thedirection 130, the angles 312, 314, and 316 are zero-degree angles inthat the light rays 118 d, 118 d′, and 118 d″ are reflected directlyback along the path of the light rays 118 c, 118 c′, and 118 c″,respectively. Also, in such embodiments, when the light reflectingsurfaces that reflect the light rays 118 c, 118 c′, and 118 c″ as rays118 d, 118 d′, and 118 d″ are aligned parallel to the direction 130, theangles from the imaging surface 110 to the rays 118 d, 118 d′, and 118d″ are 90-degree angles.

Also, in such embodiments with the beamsplitter having a 45-degreereflective surface and its length being aligned in parallel to themicro-mirror chip and the imaging surface, a light ray of 100% intensity(e.g., light rays 118 b, 118 b′, and 118 b″) can be split by abeamsplitter (e.g., the beamsplitter 112) to two light rays each of 50%intensity (e.g., the light rays 118 c, 118 c′, and 118 c″ and 118 e, 118e′, and 118 e″). One of the two split light rays of 50% intensity canreflect from the beamsplitter towards the micro-mirror chip and theother split light ray of 50% intensity passes through the beamsplittertowards the back of the beamsplitter. When the 50% intensity light rayreflects down to the image surface, on its way to the image surface itcan split again at the beamsplitter 112 such that a light ray of 25% ofthe original 100% intensity is received by the imaging surface (e.g.,the light ray 118 dd, 118 dd′, and 118 dd″).

FIG. 4 illustrates some parts of the apparatus 100 illustrated in FIG. 1, and further illustrates mechanisms for displacements (such asdisplacements 404, 404′, and 404″) of reflected light rays on theimaging surface 110 of the image sensor 104 of the apparatus 100 todetermine the intensity of electromagnetic radiation at correspondinglocations of micro mirrors 202 of the micro-mirror chip 102 of theapparatus 100. FIG. 4 also shows the micro-mirror chip 102 in the samelevel of detail as FIG. 2 , and depicts the integration of themicro-mirror chip 102 with the beamsplitter unit 106 and the imagesensor 104.

Regarding the mechanisms for displacements, FIG. 4 shows dotted arrows402, 402′, and 402″ that represent the positions of the correspondinglight rays reflected by respective micro mirrors 202 in initial dottedline positions of the respective micro mirrors 202. After the micromirrors 202 rotate from the dotted line position to the solid lineposition (as a consequence of absorbing or sensing sufficient radiationto rotate the mirrors), the light rays of the rotated micro mirrors 202move from the initial location to a subsequent location as illustratedby the solid arrows 118 dd, 118 dd′, and 118 dd″.

The measurements of the light ray displacements 404, 404′, and 404″ canbe used to compute an angle of rotation of the corresponding micromirrors 202. The rotation of a respective one of micro mirrors 202 isproportionately a function of the radiation intensity on the respectiveone of the radiation absorption surfaces 204 of a respective micromirror; thus, the measured displacements 404, 404′, and 404″ can be usedto calculate the radiation intensity on the radiation absorptionsurfaces 204 of the micro mirrors 202.

The measurement of the light ray displacement (e.g., displacements 404,404′, and 404″) can be performed for each one of micro mirrors 202 andused to determine the distribution of the radiation intensity on asingle micro mirror or on an array of the micro mirrors. The measurementcan be performed by a computational unit, which can be mounted on thePCB or can be part of the CMOS image sensor (e.g. an ASIC).

In one embodiment, a photodetector is used to capture the image formedon the imaging surface 110 of the image sensor 104, identify individuallight spots derived from corresponding light rays and corresponding torespective micro mirrors 202, determine the locations of the lightspots, and compute displacements of the respective light spotscorresponding to the displacements of the light rays (such asdisplacements 404, 404′, and 404″); and thus, compute the lightintensity associated with the radiation intensity on the micro mirrors202.

As shown in FIGS. 2 and 4 , the y-axis is in the direction of the row ofmicro mirrors 202 and is parallel to the imaging surface 110 as well asthe direction 130 described herein. The light ray displacements 404,404′, and 404″, and hence the corresponding light spot displacements onthe imaging surface 110, are along the y-axis direction. The mirrorplane 200 and the imaging surface 110 are separated by a distance 406along the z-axis that is perpendicular to the mirror plane 200 and they-axis direction. As illustrated, the height of the beamsplitter unit106 can be the distance 406.

The distance 406 along the direction perpendicular of the row of mirrors(i.e., the z-axis) can include the beamsplitter unit 106 (as shown inFIGS. 1-5 and 7-10 ). Thus, to prevent the beamsplitter unit 106 frominterfering with the reflected light from the micro-mirror chip, in someembodiments, the reflected light can travel in a path that avoids thebeamsplitter unit 106.

Not shown in the drawings, in some embodiments, light rays can bereflected from one of the plurality of light reflecting surfaces 108 atan angle from the mirror plane 200 in a direction along the x-axis inthe x-z plane. The x-z plane is perpendicular to the y-z plane of FIGS.1-5 and 7-10 . Thus, in such embodiments, light rays generally travelalong the direction of the row of micro mirrors (such as shown by micromirrors 202) onto the mirror plane 200 in the y-z plane; and, afterbeing reflected by the micro mirrors, the rays travel along the samedirection onto the imaging surface of the image sensor but skewed in thex-z plane or in the direction of the x-axis which goes into or out ofthe y-z plane of FIGS. 1-5 and 7-10 . In one embodiment, there are nostructural and/or optical components on the light path between the micromirrors and the imaging surface. In these ways for example, thereflected light can travel in a path that avoids the beamsplitter unit106 when traveling towards the imaging surface 110.

As shown in FIG. 4 , the imaging surface 110 is in parallel with themirror plane 200. Thus, when the micro mirrors 202 are in the initialpositions that are aligned with the mirror plane 200, the lightreflected by different micro mirrors 202 travels equal distances fromrespective light reflecting areas of the plurality of light reflectingsurfaces 108 of the micro mirrors to the imaging surface 110. As aresult, equal rotations of the micro mirrors 202, due to equal radiationintensity applied on the radiation absorption surfaces 204 of the micromirrors 202, result in equal light ray displacement on the imagingsurface 110. This arrangement can simplify the calibration for computingthe light intensity from the light ray displacement and/or improveaccuracy and/or ensure uniform signal generation and uniform sensitivityin the conversion from radiation intensity to light ray displacement.

FIG. 4 illustrates the measuring of displacements (e.g., displacements404, 404′, and 404″) of reflected light rays on the imaging surface 110to determine the intensity of electromagnetic radiation at the locationof micro mirrors according to one embodiment.

FIGS. 2 and 4 illustrate a single row of mirrors. However, themicro-mirror chip 102 can have multiple rows of mirrors, which cannot beshown by the two dimensions of FIGS. 1-5 and 7-10 .

Not shown in the drawings, in some embodiments, each one of the micromirrors 202 on its respective light reflecting surface of the pluralityof light reflecting surfaces 108 has a light reflecting area and anon-reflective area. The shape and size of the light reflecting area ofeach micro mirror defines a light spot reflected by the micro mirror onto the imaging surface. In some embodiments, micro mirrors of a chiphave the same shape and size in their light reflecting areas.Alternatively, different micro mirrors in a chip can have differentshapes and/or sizes in their light reflecting areas, resulting indifferently shaped reflected light spots on the imaging surfaces.

The different optical characteristics of the light reflecting areas canbe used to improve the accuracy in correlating the light spots on theimaging surface with the corresponding micro mirrors responsible forreflecting the light spots. Different optical characteristics can beachieved by using varying the shape, size, reflection rate, orientation,and/or polarization, etc. of in the reflecting surfaces of the pluralityof light reflecting surfaces 108. Further, symbols or graphical patternscan be applied (e.g., etched or overlaid) on the light reflecting areasto mark the micro mirrors such that the micro mirrors responsible forgenerating the light spots on the imaging surface can be identified fromthe shape, size, orientation, polarization, intensity and/or markers ofthe corresponding light spots captured on the imaging surface.

FIG. 5 illustrates another apparatus configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the light source 126 is part of the PCB 101 andthe beamsplitter unit 502 implements sequential beam splitting.

As shown, the apparatus 500 includes or interacts with many elementsthat are similar to elements of or that interact with the apparatus 100of FIG. 1 . Different from apparatus 100, apparatus 500 includes thebeamsplitter unit 502 that implements sequential beam splitting.

The light source 126 emits light rays including light ray 134 upwards inthe general direction of the z-axis. To reflect light towards the lens116 integrated with the beamsplitter unit 502, the enclosure 132includes the angled reflective surface 136 that is skewed from thez-axis at angle 138. In some embodiments, the angle 138 is 45 degrees sothat a center ray, e.g., light ray 134, of the light rays emitted by thelight source 126, is reflected at a 90-degree angle towards the lens116.

The sequential beam spitting is implemented by the two beamsplitters 504and 506 of the beamsplitter unit 502. The first beamsplitter 504includes a reflective surface 508 and the second beamsplitter 506includes a reflective surface 510.

As illustrated in FIG. 5 , the collimated light ray 118 b splits intotwo light rays 118 c and 118 e at the reflective surface 508 of thebeamsplitter 504. The light ray 118 c is reflected by the beamsplitter504 towards the plurality of light reflecting surfaces 108 of themicro-mirror chip 102, and the light ray 118 e transmits through thereflective surface of the beamsplitter 504. The light ray 118 c is shownreflecting off one of the reflecting surfaces of the plurality of lightreflecting surfaces 108 as light ray 118 d. The light ray 118 dtransmits through the reflective surface of beamsplitter 504 towards theimaging surface of the image sensor 104 as light ray 118 dd. The lightray 118 e is transmitted through the beamsplitter 504 to be reflectedoff the reflective surface 510 of the beamsplitter 506 as light ray 118f. The light ray 118 f is shown as reflected by the beamsplitter 506towards the plurality of light reflecting surfaces 108 of themicro-mirror chip 102. The light ray 118 f is shown reflecting off oneof the reflecting surfaces of the plurality of light reflecting surfaces108 as light ray 118 g. The light ray 118 g transmits through thereflective surface 510 of beamsplitter 506 towards the imaging surfaceof the image sensor 104 as light ray 118 gg.

The additional features of apparatus 500 and some of their alternativesare further described in related application U.S. Prov. App. Ser. No.62/791,195, filed Jan. 11, 2019, originally titled “SEQUENTIAL BEAMSPLITTING IN A RADIATION SENSING APPARATUS”. In the related applicationoriginally titled “SEQUENTIAL BEAM SPLITTING IN A RADIATION SENSINGAPPARATUS”, at least some embodiments disclosed relate toelectromagnetic radiation detection using sequential beam splitting ingeneral and more particularly but not limited to the sensing of infrared(IR) radiation using sequential beam splitting in a radiation sensingapparatus. The entire disclosure of the related application originallytitled “SEQUENTIAL BEAM SPLITTING IN A RADIATION SENSING APPARATUS” ishereby incorporated herein by reference.

FIGS. 6A, 6B, and 6C illustrate a construction of the structure of thebeamsplitter unit according to at least one embodiment where thebeamsplitter unit implements sequential beam splitting (such as thebeamsplitter unit 502 illustrated in FIG. 5 ).

A beneficial feature of a beamsplitter unit implementing sequential beamsplitting is that its height is reduced so that the apparatus using thebeamsplitter unit can have a reduced height as well. This is especiallyuseful for applications with mobile devices or applications whereapparatus height may be critical to incorporating apparatus as acomponent into another apparatus, product or system. The reduced heightof the beamsplitter unit implementing sequential beam splitting and theapparatus housing the beamsplitter unit can allow for including thebeamsplitter unit and the apparatus in a mobile device. The mobiledevice can be any electronic device small enough to be held and operatedby one or two hands of a person. For instance, the beamsplitter unitimplementing sequential beam splitting can have a height of less than 4millimeters, which allows for use of the beamsplitter unit within manydifferent types of mobile devices.

The beamsplitter unit described implementing sequential beam splittingcan be similar to a horizontal arrangement of half-sliced parts of onebeamsplitter such as the one beamsplitter illustrated in FIGS. 1-4 and7-10 . To put it another way, a beamsplitter unit implementingsequential beam splitting is similar to a device including half-slicedparts of one beamsplitter that have been rearranged so that the twohalf-sliced parts are merged sequentially in a horizontal manner.

FIG. 6A illustrates one beamsplitter 112. Beamsplitter 112 of FIG. 6Aincludes one partially-reflective surface 114 (e.g., one 45-degreereflective surface). FIG. 7B shows slices 602 and 604 of thebeamsplitter 112. The slices 602 and 604 divide the beamsplitter 112 into four parts. Two of the parts can include the beamsplitters 504 and506. And, as shown in FIGS. 6B and 6C, the beamsplitters 504 and 506 caninclude the reflective surfaces 508 and 510 of FIG. 5 respectively. FIG.6C shows the merged beamsplitters 504 and 506, which are merged intostructure 516, which is at least a part of beamsplitter unit 502 of FIG.5 . As shown, there is an area 606 in front of the beamsplitter 504, anarea 608 between the beamsplitter 504 and the beamsplitter 506, and anarea 610 behind the beamsplitter 506. The respective lengths 612 and 614of each of the beamsplitters 504 and 506 further clarify the boundariesof the areas 606, 608, and 610.

The structure 516 of FIG. 6C can be formed by initially cutting thebeamsplitter 112 according to slices 602 and 604 of FIG. 6B, and thenattaching the two parts of beamsplitter 112 that have the reflectivesurfaces 508 and 510. Also, the structure 516 of FIG. 6C can be formedby adding three blocks of transparent materials. The left-side block ofthe three blocks can include an integrated lens such as a lens similarto lens 116 of FIG. 1 . The integrated lens is not shown in FIG. 6C. Thethree blocks can provide the areas 606, 608, and 610. Along with theleft-side block (which can include an integrated lens), a second spacerblock can be attached between the beamsplitters 504 and 506, and a thirdspacer block can be attached to the right of the beamsplitter 506 toderive the structure 516 of FIG. 6C.

It can be beneficial to include the spaces provided by areas 606, 608,and 610 in a beamsplitter unit implementing sequential beam splitting.The spaces are beneficial in that they can minimize the effect inferringlight rays that occur from the different light refractions that occur inthe beamsplitter implementing sequential beam splitting. Such inferringlight rays interfere with the light rays used to detect radiation whenthere is not sufficient space between the reflecting surfaces of thebeamsplitters 504 and 506. Thus, the areas 606, 608, and 610 can providethe sufficient space to reduce interference.

Another way to reduce interference is to increase the length of eachbeamsplitter of a beamsplitter unit implementing sequential beamsplitting. Since it is desirable to include the disclosed apparatuses inmobile devices, increasing the height of beamsplitters to reduceinterference is not a practical option considering that many mobiledevices have a thin form. To reduce interference for apparatuses to beused within mobile devices, in some embodiments, the distance betweenthe micro-mirror chip and the imaging sensor is equal to or less thaneither of the lengths of the imaging sensor and the micro-mirror chip.For example, the distance between the micro-mirror chip and the imagingsensor is half or less than half of the length of the imaging sensor.Also, the distance between the micro-mirror chip and the imaging sensorcan be half or less than half of the length of the micro-mirror chip.

In some embodiments, the length of each beamsplitter of a beamsplitterunit implementing sequential beam splitting (such as each respectivelength 612 and 614 of beamsplitters 504 and 506) is at most half of thelength of the imaging sensor or the micro-mirror chip used with thebeamsplitter unit. In some embodiments including such embodiments wherethe length of each beamsplitter of the beamsplitter unit is at most halfof the length of the imaging sensor or the micro-mirror chip used withthe beamsplitter unit, the micro-mirror chip and the image sensor can bethe same length.

Also, the length of a beamsplitter unit can be greater than, less than,or equal to the lengths of the imaging sensor and the micro-mirror chip.For example, the length of the image sensor and the total length of thebeamsplitter unit can be the same or the beamsplitter unit can have agreater or lesser length than the image sensor. Also, the length of themicro-mirror chip and the total length of the beamsplitter unit can bethe same or the beamsplitter unit can have a greater or lesser lengththan the micro-mirror chip. Such variations can occur with beamsplitterunits that are implementing sequential beam splitting or not.

FIG. 7 illustrates another apparatus 702 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where a signal processing unit 702 is connected to theimage sensor 104 via the PCB 101.

As shown, the apparatus 700 includes or interacts with many elementsthat are similar to elements of or that interact with the apparatus 100of FIG. 1 . Different from apparatus 100, apparatus 700 includes thesignal processing unit 702. Alternatively, a signal processing unit canbe indirectly connected to the image sensor 104, such as a remote signalprocessing unit connected to the image sensor through a computernetwork. In other embodiments, a signal processing unit can be directlyconnected to the PCB 101, and in such examples a coupling on the PCB 101can connect the image sensor 104 and the signal processing unit (asillustrated in FIG. 7 ).

In some embodiments, a signal transmitting unit is coupled with thesignal processing unit 702 or its alternative to transmit the image datacaptured by the image sensor 104 and/or the measuring data processed bythe signal processing unit 702 or its alternative. The image datacaptured by the image sensor 104 and/or the measuring data processed bythe signal processing unit 702 or its alternative indicate the light raydisplacements (such as displacements 404, 404′, and 404″), the micromirror rotations, and the intensity of the radiation (such as theintensity of radiation rays 124 c).

The signal processing unit 702 can be programmed for customizedprocessing of designated applications. The signal processing unit 702can process the reflected light ray displacements (such as displacements404, 404′, and 404″) and generate corresponding electrical signal gains.The signal can be further processed and for example displayed to the enduser via an external display. In one example, signals processed by thesignal processing unit 702 are transmitted through a communication portwirelessly to a portable device, where the end user can see thegenerated signals and has the ability to control or interact through auser interface with the apparatus 700 or the signal processing unit 702.The signals can be transmitted and exchanged through any wired orwireless transmission method, using e.g. a USB, Bluetooth, Wi-Fi, etc.The end user's display and interface can include any device, for examplea smartphone, tablet, laptop computer, etc.

In some embodiments, the PCB can contain further surface mountedelectronic components of any kind on its front and/or backside, inaddition to the signal processing unit. In some examples, the electroniccomponents and/or the signal processing unit can be covered by a cap, orembedded in epoxy or covered and/or embedded with some material whichcan reduce the scatter of the off-cone light rays. In some embodiments,the PCB can have electronic contact pads on its frontside and/orbackside for factory calibration or operation.

Further, the backside 149 of the PCB 101 can be flat, without the pins142 to stick out of this surface. This flat surface can be used to mountthe apparatus on another flat surface on for example a host board. Insome examples, an adhesive may be used with the flat surface before itis mounted and/or fixed to a host board as a way of attaching and/orfixing this apparatus to another apparatus. In some examples, aconnection cable may be attached to the PCB and be protruding from theapparatus so it provides a way to connect electronically the apparatusto another device. The connection cable can supply operating power andexchange data and signals between the apparatus (e.g., apparatus 100 or700) and the host processor and/or device. In some examples, theconnector can stream the thermal image, or the CMOS image.

FIG. 8 illustrates another apparatus 800 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the radiation lens 120 and a radiation filter 122are within a wall 842 (such as a cylindrical wall) of an opening 840 ofthe enclosure 832 that is above the micro-mirror chip 102 and housing828 of the micro-mirror chip. As shown, the apparatus 800 includes orinteracts with many elements that are similar to elements of or thatinteract with the apparatus 100 of FIG. 1 . Different from apparatus100, apparatus 800 includes an upper exterior surface 850 that includesthe opening 840 that houses the lens 120 and the filter 122. The openingtraverses a top wall of the enclosure 832 from the exterior surface 850to the interior surface 846. The housing 828 is within the chamber 156and separated by space within the chamber from the opening 840. Thisconfiguration can be beneficial in that the lens 120 and the filter 122can be separated from the housing that contains the micro-mirror chip.

FIG. 9 illustrates another apparatus 900 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the radiation lens 120 and a radiation filter 122are within a wall 942 (such as a cylindrical wall) of an opening 940 ofthe enclosure 932. Different from apparatus 800, apparatus 900 isconfigured such that the micro-mirror chip 102 resides below the filter122 within the wall 942 of the opening 940. As shown, the apparatus 900includes or interacts with many elements that are similar to elements ofor that interact with the apparatus 100 of FIG. 1 . Different fromapparatus 100, apparatus 900 includes an upper exterior surface 950 thatincludes the opening 940 that houses the lens 120, the filter 122 andthe micro-mirror chip 102. The opening 940 traverses a top wall of theenclosure 932 from the exterior surface 950 to the interior surface 946.There is no housing for the micro-mirror chip and no space within thechamber 156 that separates the chip from the filter 122 since bothelements are contained within the opening 940. This configuration can bebeneficial in that an additional housing for the micro-mirror chip 102is not used. Also, for example, the wall 942 can facilitate directingand focusing radiation onto the micro-mirror chip 102. Also, themicro-mirror chip 102 is shown directly attached to the beamsplitterunit 106. Further, such an arrangement where the enclosure 932 is indirect contact with the beamsplitter unit 106 can be used to align theenclosure relative to the beamsplitter unit, or vice versa.

FIG. 10 illustrates another apparatus 1000 configured to measure adistribution of electromagnetic radiation according to at least oneother embodiment where the radiation lens 120 and a radiation filter 122are within a wall 1042 (such as a cylindrical wall) of an opening 1040of the enclosure 1032. Different from apparatus 800, apparatus 1000 isconfigured such that the micro-mirror chip 102 resides below the filter122 within the wall 1042 of the opening 1040 partially. As shown, theapparatus 1000 includes or interacts with many elements that are similarto elements of or that interact with the apparatus 100 of FIG. 1 .Different from apparatus 100, apparatus 1000 includes an upper exteriorsurface 1050 that includes the opening 1040 that houses the lens 120 andthe filter 122 as well as partially houses the micro-mirror chip 102.The opening 1040 traverses a top wall of the enclosure 1032 from theexterior surface 1050 to the interior surface 1046. There is no housingfor the micro-mirror chip and no space within the chamber 156 thatseparates the chip from the filter 122. This configuration can bebeneficial in that an additional housing for the micro-mirror chip 102is not used. Also, for example, the wall 1042 can sufficientlyfacilitate directing and focusing radiation onto the micro-mirror chip102. Also, the micro-mirror chip 102 is shown directly attached to thebeamsplitter unit 106, so that it is not necessarily beneficial to havethe entire chip within the wall 1042. Another example, benefit of theconfiguration of apparatus 1032 is that the chamber 156 is more flexiblefor different sized beamsplitter units. Since the height of chamber 156of apparatus 1032 is greater than the height of chamber 156 of apparatus932.

In some embodiments, a micro-mirror chip does not have a housing and itis glued directly on the beamsplitter unit. The beamsplitter unit can bealigned on a PCB through pins or can be aligned on a CMOS by a recess.The radiation filter 122 is optional and can be left out in someembodiments. A single element lens is sufficient, which can be gluedinside the housing and which provides light and/or hermetic isolation.

In some examples, the light directing device can be a prism or have adifferent shape than presented in the drawings, also the surface 114 canbe a small airgap or consist of different material. Surface 136 can bepartially patterned reflective surface to block stray light.

Also, described herein is a printed circuit board arrangement with aflexible part for an electromagnetic radiation detector. In someembodiments, the electromagnetic radiation sensing using beam splittingin a radiation sensing apparatus includes the light source mounted on aflexible part (e.g., see the flexible part 1202 depicted in FIG. 12 ).In other words, variations of the apparatuses described herein caninclude a light source mounted to a flexible part (e.g., see theflexible part 1202 depicted in FIG. 12 ). In some embodiments, a lightsource, such as a light-emitting diode (LED), is attached to a flexiblepart of the radiation sensing apparatus or a flexible part of the PCB(printed circuit board) in which the apparatus is attached (e.g., seethe flexible part 1202 depicted in FIG. 12 ). By bending the flexiblepart, a beam emitted from the light source can be directed towards abeamsplitter (e.g., see FIG. 12 ).

With using the flexible part, the light ray from the light source (suchas from an LED) can hit the beamsplitter perpendicularly. Also, thelight source can be fixed to the PCB. In some embodiments, the lightsource can be fixed to a flexible part of the PCB or a flexible part ofthe apparatus that is attached to the PCB. Also, in some embodiments(not depicted), the apparatus can include a reflective wall (e.g.,reflective surface 136 depicted in at least FIG. 1 ) and a flexible part(e.g., see the flexible part 1202 depicted in FIG. 12 ), such that theflexible part is flexed so that a beam is emitted towards the reflectivesurface from a light source mounted to the flexible part, and thenreflected towards the beamsplitter from the reflective surface.

In some embodiments, the light source is attached to a flexible part ofthe PCB and the flexible part is bent upwards. In such example, theflexible part can be attached on a vertical side (front) wall of thehousing of the apparatus. The wall can have a small opening (such as apinhole) for the light source to emit beams through the opening.

In some embodiments, the flexible part (flex PCB) is part of the PCB. Astiffener and a low-profile board-to-board connector can connect theflex PCB to a main PCB in the assembly. Also, a lens and the outer wallsof the apparatus can include a molded plastic shell glued on the PCB.The lens can be the lens 120 as shown in FIG. 12 .

In the foregoing specification, embodiments of the disclosure have beendescribed with reference to specific example embodiments thereof. Itwill be evident that various modifications can be made thereto withoutdeparting from the broader spirit and scope of embodiments of thedisclosure as set forth in the following claims. The specification anddrawings are, accordingly, to be regarded in an illustrative senserather than a restrictive sense.

What is claimed is:
 1. An apparatus comprising: a beamsplitter; and areflector, wherein: the beamsplitter and the reflector are configured tobe positioned along an axis parallel to a surface of a micro-mirror chipsituated proximate to the apparatus; the beamsplitter comprises apartially-reflective surface that is oblique to the axis, thepartially-reflective surface configured to split a first light ray froma light source into a second light ray and a third light ray; thebeamsplitter is configured to direct the second light ray toward a firstportion of the micro-mirror chip and direct the third light ray towardthe reflector; and the reflector comprises a surface that is at leastpartially reflective and is oblique to the axis, the surface configuredto reflect at least a portion of the third light ray toward a secondportion of the micro-mirror chip.
 2. The apparatus of claim 1, whereinthe beamsplitter is a first beamsplitter, and wherein the reflectorcomprises a second beamsplitter, such that the surface of the reflectorsplits the third light ray into a fourth light ray and a fifth lightray.
 3. The apparatus of claim 2, wherein the fourth light ray isreflected toward the second portion of the micro-mirror chip.
 4. Theapparatus of claim 2, wherein the fifth light ray passes through thesurface.
 5. The apparatus of claim 4, wherein the fifth light ray passesthrough the surface toward a housing of the apparatus.
 6. The apparatusof claim 1, wherein the micro-mirror chip comprises a plurality of lightreflecting surfaces.
 7. The apparatus of claim 6, wherein themicro-mirror chip is configured to reflect light toward an image sensorcomprising an imaging surface.
 8. The apparatus of claim 7, wherein thelight reflected toward the image sensor passes through the apparatus. 9.The apparatus of claim 1, wherein the partially-reflective surface isoriented at approximately a 45-degree angle with respect to the axis.10. The apparatus of claim 1, wherein the surface of the reflector isoriented at approximately a 45-degree angle with respect to the axis.11. The apparatus of claim 1, further comprising a lens through whichthe first light ray passes between the light source and thebeamsplitter.
 12. The apparatus of claim 1, wherein thepartially-reflective surface extends through a first length of thebeamsplitter and the surface of the reflector extends through a secondlength of the beamsplitter.
 13. The apparatus of claim 12, wherein thebeamsplitter comprises an area between the first length of thepartially-reflective surface and the second length of the reflector inwhich there is no reflective surface.
 14. The apparatus of claim 12,wherein the beamsplitter comprises an area between where the first lightray enters the beamsplitter and the first length of thepartially-reflective surface in which there is no reflective surface.15. The apparatus of claim 12, wherein the beamsplitter comprises anarea between the second length of the reflector and a rear surface ofthe beamsplitter in which there is no reflective surface.
 16. Theapparatus of claim 1, wherein the wherein the apparatus is less than 4millimeters in height.
 17. An apparatus comprising: a micro-mirror chipcomprising a plurality of light reflecting surfaces; an image sensorcomprising an imaging surface; and a beamsplitter unit located betweenthe micro-mirror chip and the image sensor, wherein the beamsplitterunit comprises a beamsplitter and a reflector, and further wherein: thebeamsplitter and the reflector are positioned along an axis parallel toa surface of the micro-mirror chip proximate to the beamsplitter unit;the beamsplitter comprises a partially-reflective surface that isoblique to the axis, the partially-reflective surface configured tosplit a first light ray from a light source into a second light ray anda third light ray; the beamsplitter is configured to direct the secondlight ray toward a first portion of the micro-mirror chip and direct thethird light ray toward the reflector; and the reflector comprises asurface that is at least partially reflective and is oblique to theaxis, the surface configured to reflect at least a portion of the thirdlight ray toward a second portion of the micro-mirror chip.
 18. Theapparatus of claim 17, wherein the first portion of the micro-mirrorchip is a first half of the micro-mirror chip and the second portion ofthe micro-mirror chip is a second half of the micro-mirror chip.
 19. Theapparatus of claim 17, wherein: the beamsplitter unit comprises a firstarea between the first length of the partially-reflective surface andthe second length of the reflector in which there is no reflectivesurface; the beamsplitter unit comprises a second area between where thefirst light ray enters the beamsplitter and the first length of thepartially-reflective surface in which there is no reflective surface;and the beamsplitter unit comprises a third area between the secondlength of the reflector and a rear surface of the beamsplitter in whichthere is no reflective surface.
 20. An apparatus comprising: a firstbeamsplitter; and a second beamsplitter, wherein: the first beamsplitterand the second beamsplitter are configured to be positioned along anaxis parallel to a surface of a micro-mirror chip positioned adjacent tothe apparatus; the first beamsplitter comprises a firstpartially-reflective surface that is oblique to the axis, the firstpartially-reflective surface configured to split a first light ray froma light source into a second light ray and a third light ray; the firstbeamsplitter is configured to direct the second light ray toward a firstportion of the micro-mirror chip and direct the third light ray towardthe second beamsplitter; and the second beamsplitter comprises a secondpartially-reflective surface that is oblique to the axis, the secondpartially-reflective surface configured to reflect at least a portion ofthe third light ray toward a second portion of the micro-mirror chip.